These books sound like they're for 8-10 year olds, but they're not. I'd say they're for ages 10+ because there's A LOT of violence in some of them and major characters die, but they're not that bad and I don't find them upsetting. They're about 4 children aged 9-12 in Roman times who do random stuff. As well as being really well-written, they also have lots of facts about peoples' lives and culture a long time ago, which is interesting.